Towards an Understanding of Factors Controlling Seed Bank Composition and Longevity in the Alpine Environment

The ability of seeds to regenerate from soil seed banks has long been recognized as a key survival strategy for plants establishing new niches in highly variable climates of alpine environments. However, the fundamental aspects of evolutionary/selective forces for seed bank development in alpine ecosystems are largely unknown. Here, we developed a model that describes dormancy, a high temperature requirement and a specific light/darkness regime at the time of seed shedding can preclude autumn germination, thus contributing to seed persistence until the next growing season. The benefits of these factors synchronising germination with the growing season are reviewed. Additionally, the importance of climatic variations of maternal environment affecting some of these factors is also discussed. It is suggested that the environmental conditions during the growing season partly control the seed persistence and seeds that fail to germinate are carried over to the next season. Species that have small (<3 mg) and round-shaped seeds tend to persist more easily in soil for over five years, than do the large or flat seeds. However, some large-seeded species also have the potential to establish short-term persistence bank. A literature survey reveals 88% of the alpine seeds have a mass <3 mg. Seed size has only a weak relationship with mean germination timing (MGT) indicating that reduced persistence in large-seeded species cannot be counteracted by quicker germination, but combined effects of other factors stimulating germination remain an open area to be studied. It is proposed that long distance dispersal (LDD) is limited in most-but not all-species, primarily due to the absence of specialized dispersal structures. However, among numerous dispersal modes, most species tend to be dispersed by wind. Thus, spermatophytes of alpine environments have a greater tendency to establish seed banks and spread the risk of germination to many years, rather than being dispersed to other micro-climates

Genetic characterization of Porcine Circovirus 2 found in Malaysia

Background: Porcine circovirus type 2 is the primary etiological agent associated with a group of complex multi-factorial diseases classified as Porcine Circovirus Associated Diseases (PCVAD). Sporadic cases reported in Malaysia in 2007 caused major economic losses to the 2.2 billion Malaysian ringgit (MYR) (approximately 0.7 billion US dollar) swine industry. The objective of the present study was to determine the association between the presence of PCV2 and occurrences of PCVAD. Results: This study showed that 37 out of 42 farms sampled were positive for PCV2 using PCR screening. Thirteen whole genome of PCV2 isolates from pigs with typical PCVAD symptoms were successfully sequenced. These isolates shared 98.3-99.2% similarities with sequences of isolates from the Netherlands. All thirteen isolates fell into the same clade as PCV2b isolates from other countries. Amino acid sequence analysis of the putative capsid protein (ORF2) of the PCV2 revealed that there are three clusters found in Malaysia, namely cluster 1C and 1A/1B. Of interest, three of the isolates (isolates Mal 005, Mal 006 and Mal 010) had a proline substitution for arginine or isoleucine encoded at nt. position 88-89. Eight of the isolates had mutations at the C terminus of the putative capsid protein suggestive of higher pathogenicity which may account for the high reports of PCVAD clinical symptoms in 2007. Conclusion: Phylogenetic study suggests that there may be a link between movements of animals by import of breeders into the country being the route of entry of the virus. While it is not possible to eradicate the virus from commercial pigs, the swine industry in Malaysia can be safeguarded by control measures implemented throughout the country. These measures should include improved biosecurity, disease surveillance; vaccination as well as enforcement of regulations formulated to control and prevent the spread of this disease on a national scale

Rare earth element (REE) lanthanum doped zinc oxide (La: ZnO) nanomaterials: synthesis structural optical and antibacterial studies

Lanthanum (La) doped zinc oxide (ZnO) nanomaterials (LaxZn1-xO, x = 0.0, 0.03, 0.05, 0.07 M) were synthesized via co-precipitation method using zinc acetate, lanthanum nitrate as precursors, octylamine as capping and reducing agent. The structures, morphologies, optical activity and antibacterial properties of LaxZn1-xO were investigated by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, High resolution scanning electron microscopy (HR-SEM), Energy dispersive X-ray (EDX), UV–Visible, Photoluminescence (PL) spectroscopy. The antibacterial activities of LaxZn1-xO were tested by modified disc diffusion method. The XRD results showed that the La3+ ions were successfully incorporated into the ZnO host, and the products were well-crystalline. The average size of undoped and doped La-doped ZnO was found to be in the ranges from 15.64 to 10.18 nm. In addition, the sphere-like nanoparticles morphology of LaxZn1-xO was confirmed by HR-SEM images. The band gap of La-doped ZnO nanoparticles were varied with the La3+ ions doping concentration. In addition, increasing the doping concentration of La3+ ions in ZnO increases the defects in ZnO lattice and hence resulting red-shift in UV emission, which indicate the presence of narrow band-gap in doped nanoparticles

Identification of QTLs and candidate genes for high grain Fe and Zn concentration in sorghum [Sorghum bicolor (L.)Moench]

Sorghum is a major food crop in the semi-arid tropics of Africa and Asia. Enhancing the grain iron (Fe) and zinc (Zn) concentration in sorghum using genetic approaches would help alleviate micronutrient malnutrition in millions of poor people consuming sorghum as a staple food. To localize genomic regions associated with grain Fe and Zn, a sorghum F6 recombinant inbred line (RIL) population (342 lines derived from cross 296B PVK 801) was phenotyped in six environments, and genotyped with simple sequence repeat (SSR), DArT (Diversity Array Technology) and DArTSeq (Diversity Array Technology) markers. Highly significant genotype environment interactions were observed for both micronutrients. Grain Fe showed greater variation than Zn. A sorghum genetic map was constructed with 2088 markers (1148 DArTs, 927 DArTSeqs and 13 SSRs) covering 1355.52 cM with an average marker interval of 0.6 cM. Eleven QTLs (individual) and 3 QTLs (across) environments for Fe and Zn were identified. We identified putative candidate genes from the QTL interval of qfe7.1, qzn7.1, and qzn7.2 (across environments) located on SBI-07 involved in Fe and Zn metabolism. These were CYP71B34, and ZFP 8 (ZINC FINGER PROTEIN 8). After validation, the linked markers identified in this study can help in developing high grain Fe and Zn sorghum cultivars in sorghum improvement programs globally

Fine mapping studies identified a 113 kb region within “QTL-hotspot_a” for seed weight and drought related traits in chickpea

A “QTL-hotspot” region of 7 Mb size for drought component traits was identified on CaLG04, using a recombinant inbred line (RIL) population (ICC 4958 × ICC 1882) in chickpea. Further, skimbased genotyping by sequencing (GBS) approach with large SNP markers delimited the “QTL-hotspot” region into two sub-regions; viz, “QTL-hotspot_a” of 139.22 kb and “QTL-hotspot_b” of 153.36 kb, on the kabuli draft genome sequence. In order to validate and identify more recombinations in the sub-regions for further refinement, a fine mapping population with 1,911 lines was developed. Flanking markers of the two “QTL-hotspot” sub-regions were converted to KASPar assays and used to screen the fine mapping population consisting of 1,911 lines. As a result, 19 F2:3 recombinant families were identified. These families were phenotyped for seed weight and other drought-related traits. Comparison of genotype and phenotype data identified a genomic region of ~113 Kb size within “QTL-hotspot_a” responsible for 100 seed weight (100SDW) and other drought-related traits in chickpea. Subsequently, a syntenic study between the refined “QTL-hotpsot” region and desi genome identified a 2 Mb region on Ca_LG_4 pseudomolecule. Whole genome re-sequencing (WGRS) analysis of selected lines from each recombinant family identified several non-synonymous and InDel mutations within important candidate genes. Functional validation of these genes will help decipher the mechanism of drought stress tolerance in chickpea

Enhancement of immune response of HBsAg loaded poly(L-lactic acid) microspheres against Hepatitis B through incorporation of alum and chitosan

Purpose: Poly (L-lactic acid) (PLA) microparticles encapsulating Hepatitis B surface antigen (HBsAg) with alum and chitosan were investigated for their potential as a vaccine delivery system. Methods: The microparticles, prepared using a water-in-oil-in-water (w/o/w) double emulsion solvent evaporation method with polyvinyl alcohol (PVA) or chitosan as the external phase stabilising agent showed a significant increase in the encapsulation efficiency of the antigen. Results: PLA-Alum and PLA-chitosan microparticles induced HBsAg serum specific IgG antibody responses significantly higher than PLA only microparticles and free antigen following subcutaneous administration. Chitosan not only imparted a positive charge to the surface of the microparticles but was also able to increase the serum specific IgG antibody responses significantly. Conclusions: The cytokine assays showed that the serum IgG antibody response induced is different according to the formulation, indicated by the differential levels of interleukin 4 (IL-4), interleukin 6 (IL-6) and interferon gamma (IFN-γ). The microparticles eliciting the highest IgG antibody response did not necessarily elicit the highest levels of the cytokines IL-4, IL-6 and IFN-γ

Acute Human Self-Poisoning with Imidacloprid Compound: A Neonicotinoid Insecticide

Background: Deliberate self-poisoning with older pesticides such as organophosphorus compounds are commonly fatal and a serious public health problem in the developing world. The clinical consequences of self-poisoning with newer pesticides are not well described. Such information may help to improve clinical management and inform pesticide regulators of their relative toxicity. This study reports the clinical outcomes and toxicokinetics of the neonicotinoid insecticide imidacloprid following acute self-poisoning in humans. Methodology/Principal Findings: Demographic and clinical data were prospectively recorded in patients with imidacloprid exposure in three hospitals in Sri Lanka. Blood samples were collected when possible for quantification of imidacloprid concentration. There were 68 patients (61 self-ingestions and 7 dermal exposures) with exposure to imidacloprid. Of the self-poisoning patients, the median time to presentation was 4 hours (IQR 2.3–6.0) and median amount ingested was 15 mL (IQR 10–50 mL). Most patients only developed mild symptoms such as nausea, vomiting, headache and diarrhoea. One patient developed respiratory failure needing mechanical ventilation while another was admitted to intensive care due to prolonged sedation. There were no deaths. Median admission imidacloprid concentration was 10.58 ng/L; IQR: 3.84–15.58 ng/L, Range: 0.02–51.25 ng/L. Changes in the concentration of imidacloprid in serial blood samples were consistent with prolonged absorption and/or saturable elimination. Conclusions: Imidacloprid generally demonstrates low human lethality even in large ingestions. Respiratory failure and reduced level of consciousness were the most serious complications, but these were uncommon. Substitution of imidacloprid for organophosphorus compounds in areas where the incidence of self-poisoning is high may help reduce deaths from self-poisoning

Modelling the sulfate capacity of simulated radioactive waste borosilicate glasses

The capacity of simulated high-level radioactive waste borosilicate glasses to incorporate sulfate has been studied as a function of glass composition. Combined Raman, 57Fe Mössbauer and literature evidence supports the attribution of coordination numbers and oxidation states of constituent cations for the purposes of modelling, and results confirm the validity of correlating sulfate incorporation in multicomponent borosilicate radioactive waste glasses with different models. A strong compositional dependency is observed and this can be described by an inverse linear relationship between incorporated sulfate (mol% SO42−) and total cation field strength index of the glass, Σ(z/a2), with a high goodness-of-fit (R2 ≈ 0.950). Similar relationships are also obtained if theoretical optical basicity, Λth (R2 ≈ 0.930) or non-bridging oxygen per tetrahedron ratio, NBO/T (R2 ≈ 0.919), are used. Results support the application of these models, and in particular Σ(z/a2), as predictive tools to aid the development of new glass compositions with enhanced sulfate capacities